Use the prepositions below to complete the passage. Some prepositions may be used more than once. over - on - down - in - from - at Plankton Plankton, the most basic part of the ocean food chain, is found (1) ....................... huge amounts (2) ................................ the oceans of the world. Slightly (3) .......................... half of it consists of tiny plants called diatoms. The rest is microscopic animals and fish eggs. (4) ............................... the Arctic Ocean to the Antarctic Ocean, it is relied (5) ..................................... as a food source by many fish. (6) ........................... areas where there is no plankton, such as (7) ............................... the bottom of the sea, there are fewer fish and they eat whatever floats (8) ...................................... to them. The small fish that live (9) .................................. plankton are, (10) ............................. turn, eaten by larger fish. Even larger fish feed (11) ................................. them. The whole cycle of life in the sea depends (12) .................................. plankton.